1. Field of the Invention
This invention relates to a vibratory parts-feeder apparatus and more particularly to a vibratory parts-feeder apparatus in which noises generated from a vibratory parts-feeder can be cancelled.
2. Description of the Prior Art
FIG. 1 shows a Prior Art vibratory parts-feeder and it is generally denoted by a reference numeral 1. A spiral track is formed on the inner surface of a bowl 2. It is nearly circular in plan view. The bowl 2 is combined with a base block 3 by plural leaf springs 5 obliquely arranged at regular angular intervals. A movable core 4 is fixed at the bottom of the bowl 2. It is facing to an electro-magnet 7 spacing by a gap g. When an electro-magnetic coil 6 wound on the electro-magnet 7 is energized by alternating current, an alternating magnetic attracting force is generated between the movable core 4 and electro-magnet 7. Thus, the bowl 2 is tortionally vibrated in a well-known manner. The base block 3 is supported by rubber springs 8 which function to prevent vibrational force from transmitting to the ground S. The rubber spring 8 is fixed at the ground S through a fixing plate 9 by a bolt.
A torsional vibratory force generator is composed of the movable core 4, the electro-magnet 7, the electro-magnetic coil 6 and the leaf springs 5. The whole of the torsional vibratory generator is covered by a cylindrical cover member 10. The above described vibratory parts-feeder 1 widely used to supply different parts to a next stage desired posture. Recently, small parts such as semi-conductor device and electronic part are widely handled by the vibratory parts-feeder 1. The size of the part is, for example, 1 mm.times.2 mm.times.0.5 mm. It is difficult to obtain a satisfactory orientating function at the commercial electric source frequency supply of 50 Hz or 60 Hz. Accordingly, a driving frequency of the electric-magnetic coil is increased to a higher frequency such as 100 Hz, while an amplitude of this bowl is smaller. The small parts can be sufficiently orientated. However, the level of the sound generated from the vibratory parts-feeder driven by the high-frequency is very high and the sound is jarring. It is a public nuisance to the neighborhood.